In constructing various structures with cement compositions, e.g., concrete, it is often necessary to seal, or waterproof, the joints between adjacent sections of concrete.
For example, water seals typically are used, in the construction of concrete sections, where concrete joints become necessary. Such water seals are common between two preformed or precured concrete sections, or at a joint between one precured or partially cured concrete section and a concrete section being poured. More specifically, waterproofing articles for sealing concrete joints, for example, may be used during construction of the following structures: precast concrete wall systems; septic tanks and sewage treatment plants; sanitary and storm sewer manholes; pipe, including round, oval, flatbase, elliptical and arch types; cold joints in foundation slabs or walls below grade; burial and utility vaults; wet wells; box culverts; waste water treatment plants; and portable water tanks. A functional waterproofing seal should provide a complete water barrier to prevent water infiltration.
Joints between adjacent concrete sections, such as those used during the construction of the above-mentioned structures, may be made as socket-and-plug or male-female type joints. These joint types sometimes are particularly problemsome in providing a complete waterproof seal due to insufficient dimensional accuracy, improper field work at the construction site, and/or uneven settling of the land on which the concrete structure is placed.
When a water-expandable waterproofing composition is disposed to bridge the joint between (a) a cured or partially cured section of concrete and (b) a newly poured concrete section, being poured adjacent to the cured or partially cured concrete section, expansion of the waterproofing composition results in forces against one or both of the concrete sections from the expanding waterproofing composition. The shaped waterproofing composition of the present invention minimizes the stress and/or expansion forces exerted against one or both of the adjacent concrete sections from the expanding waterproofing article.
Another substantial problem frequently encountered when using a water-expandable, waterproofing article to seal a joint between two concrete sections is that the waterproofing article can be deformed or displaced from its intended position at the joint. Deformation and/or displacement can result since the waterproofing article is formed from a composition that is relatively soft and can be deformed and/or displaced easily upon impact from concrete being poured onto the composition. For example, when a water seal article is placed on an upper surface of a first concrete section that is at least partially cured, and a second concrete section is newly poured adjacent to the first concrete section, the falling concrete that impacts the water seal article oftentimes forces the article out of place, so that the article no longer bridges the two concrete sections completely along this joint.
A useful water seal article should have additional beneficial qualities. Such a seal should be useful in all environmental temperatures encountered at the installation location without becoming too stiff and brittle in cold temperatures, and without becoming so soft at higher temperatures that the composition flows by gravity and is thereby displaced from its intended location. Also, the seal should remain flexible over time without shrinking, substantial hardening or oxidizing. Further, a water seal article should be safe to use.
Bentonite clay, particularly sodium bentonite, often has been used in waterproofing applications, including foundation waterproofing, due to its known ability to expand, upon hydration, to fill areas of potential water flow. Bentonite clay swells to many times its non-hydrated volume when it comes into contact with water, forming a water-impenetrable clay layer that protects an adjacent structure. The hydrated clay composition expands sufficiently to seal relatively large seams or joints between concrete sections as well as relatively small cracks in concrete.
Installing water seals in concrete joints has been a time consuming and labor-intensive part of concrete construction. Therefore, a useful seal should not only allow for a complete, quality seal between concrete sections, but it should be capable of relatively easy and cost-efficient installation.
The water seal of the present invention satisfies all of the criteria set forth above.